An intergeneric hybridization was attempted between Chinese cabbage (Brassica campestris ssp. pekinensis: cv. Sam Jin and Ken Shin) and radish (Raphanus sativus: Jinju Daepyung) in 1981 and 1982.
Reciprocal difference was clearly observed. While no siliques were developed when radish was used as a female parent, per centage of silique formation reached up to 80% when Chinese cabbage was used as a female parent. However, the developed siliques were turned out to be empty, no mature hybrid seeds found, which was considered due to embryo abortion.
In order to overcome the genetic barrier, the embryo abortion in case of intergeneric crossing between Chinese cabbage and radish, both ovary and ovule culture were attempted with various media and different combination of concentration of two growth regulators, namely NAA and kinetin. From ovary culture, a few small seeds were obtained but all of them didn´t germinate. The best results were obtained when fertilized ovules were detached from mother plant 10 to 15 days after pollination and cultured on White´s medium supplemented with rather low concentration of NAA(0.1 to 1㎎/ℓ) and kinetin (0.1 to 1㎎/ℓ).
After about 70 days of culture, five apparently intergeneric F₁ hybrid seedlings with normal shoots and roots were obtained, but all except one died during the transplanting into the pot containing vermiculite. The remaining was grown vigorously and flowered after vernalization, but was completely sterile producing no F₁´s seeds. The meiosis of the F₁´s PMC showed both bivalent and univalents.
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